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At least 991 records · Page 55Linked to original sources
PubMed1990

Determination of salicylic acid and its metabolites in urine by derivative synchronous spectrofluorimetry.

The simultaneous determination of salicylic acid in binary and/or ternary mixtures and its two main urinary metabolites is proposed. Mixtures of salicylic, salicyluric and gentisic acids are resolved by synchronous spectrofluorimetry, in combination with first-derivative measurements. The urine is extracted with diethyl ether in acid medium. Salicylic and salicyluric acids are re-extracted into glycine-sodium hydroxide buffer solution of pH 11.6 and determined at that pH, and salicylic and gentisic acids are re-extracted into boric acid-sodium hydroxide buffer solution of pH 8.5 and determined at pH 6.

Gentisates↗
PubMed1989

Tetrafluoroboric acid, a useful deprotecting reagent in peptide synthesis.

We have found that tetrafluoroboric acid (HBF4) in trifluoroacetic acid (TFA) in the presence of thioanisole cleaves various protecting groups currently used in peptide synthesis. HBF4 in TFA cleaves an amino acid amide from 4-methylbenzhydrylamine resin more effectively than trifluoromethanesulfonic acid in TFA. Lamprey gonadotropin-releasing hormone (a 10-residue peptide amide) was synthesized using 1 M HBF4-thioanisole in TFA by both solution-phase and solid-phase methods.

Amino Acid Sequence↗
PubMed1985

Effect of urine preservation on urine screening and organism identification.

Three urine preservation-transport methods were examined for their effect on rapid urine-screening procedures. Results from fresh urine specimens, screened for bacteriuria by leukocyte esterase, nitrate, Autobac, Bac-T-Screen, Auto Microbic System (AMS), and bioluminescence procedures, were compared with urine-screen results from urine specimens held for 24 hours at room temperature in chemical preservatives. Quantitative discrepancies ranged from 0%, for urine preserved with glycerin-boric acid-sodium formate and tested by AMS or leukocyte esterase, to 21% for urines in the same preservative tested by bioluminescence or nitrate. Up to 62% of the organism identifications made from preserved urine specimens tested by the AMS urine card were in error. These data suggest that it may be inadvisable to use weak organic acid-based urine preservation systems in conjunction with these urine-screen procedures.

Bacteriuria↗
PubMed1991

Microbial stabilization of antibiotic-containing urine samples by using the FLORA-STAT urine transport system.

The FLORA-STAT Urine Transport System (Wadley Biosciences Corp./Lymphokine Partners Ltd., Dallas, Tex.) was evaluated for its efficacy in maintaining organism count and in effectively blocking the bactericidal action of therapeutic antimicrobial agents in urine samples when the urine samples were held at room temperature. Reconstructions with 53 organism-antimicrobial combinations were performed at 0, 4, 8, and 24 h in which the FLORA-STAT system was compared with two boric acid-based systems (Urine C&S Transport Kit [Becton Dickinson VACUTAINER Systems, Rutherford, N.J.]; Sage Urine Collection Kit for Culture [Sage Products, Inc., Cary, Ill.]) and untreated urine. At 24 h, less than 1-log-unit changes in organism counts were found in 100, 92, and 10% of the urine samples without antimicrobial agents and in 97, 65, and 16% of the urine samples with antimicrobial agents for FLORA-STAT-treated, boric acid-treated, and untreated urine samples, respectively. The FLORA-STAT system was further evaluated by sending split samples prepared from laboratory-inoculated patient urine samples (57 without and 50 with antimicrobial agents) to four commercial laboratories by using their respective transport devices and procedures. Samples were also sent to a local reference laboratory which provided prompt processing. Each laboratory received independently labeled transport devices containing untreated, FLORA-STAT-treated, and preservative-treated (if provided by the commercial laboratory) samples prepared from the same urine specimen of a patient. Average estimated transport times ranged from 13 to 24 h for the commercial laboratories; the transport time was less than 4 h for the local reference laboratory.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗
PubMed1977

Effect of three ophthalmic solutions on chemical conjunctivitis in the neonate.

In an attempt to reduce chemical conjunctivitis after silver nitrate prophylaxis, three different ophthalmic solutions (sodium chloride, sterile water, and a boric acid-sodium borate solution) were used to irrigate the eyes immediately after prophylaxis in 450 neonates. Sterile water significantly reduced (P less than .02) the prevalence of chemical conjunctivitis when compared to the conventional sodium chloride rinse. A significantly greater prevalence of chemical irritation in low-birth-weight infants was also noted (P less than .02).

Boric Acids↗
PubMed1996

Enhanced field strength and resolution in gel electrophoresis upon substitution of buffer by histidine at its isoelectric point.

Gel electrophoresis in isoelectric buffers, recently introduced by R. Westermeier and H. Schickle (Electrophoresis '95, Paris, Abstract No.3, 1995), was applied to the automated HPGE-1000 apparatus in the expectation to be able to increase the field strength under the limiting conditions of heat dissipation capacity and voltage of that apparatus. A previous attempt to achieve that aim by reduction of gel thickness had not yielded more than a twofold increment in resolving power. Replacing 0.2 X Tris-boric acid-EDTA (TBE) buffer, conventionally applied in the apparatus at 15 V/cm, by 0.05 M histidine, pH 7.6 (close to the pI of 7.47), allows one to increase the field strength to 60 V/cm, thus providing a nearly fivefold increment in resolution under otherwise identical conditions (fluorescein carboxylate-labeled conalbumin-sodium dodecyl sulfate (SDS) and soybean trypsin inhibitor-SDS samples, 10 degrees C, 4% MetaPhor agarose). An additional decrease in band dispersion can be obtained by decreasing the starting zone width through buffer dilution in the sample phase.

Boric Acids↗
PubMed1995

Oral Candida albicans biotypes in Chinese patients with and without oral candidosis.

A total of 53 oral Candida albicans isolates from Chinese patients with clinically diagnosed oral candidosis (27 patients) or without overt signs and mycological manifestations of infection (26) were biotyped using two commercially available API micromethod kits and a boric acid-resistance test. There were no significant differences in the biotypes in health and disease, although the biotype A1R was present only in diseased individuals. The biotype A1S accounted for 21% of the total isolates, as in a number of other previous studies from the West. However, 14 of the 27 biotypes characterized were new biotypes that have not been described before. These preliminary data indicate that biotypic profile of C. albicans may bear no relation to the virulence of the isolates, and that diverse subtypes of the fungus are globally prevalent.

Boric Acids↗
PubMed1984

[Specimen carriers for blood sugar determinations].

The use of boric acid-impregnated filter paper has proven to be a useful and reliable means of absorbing capillary blood samples for determining glucose concentration. In this method a circular piece of filter paper (6.36 mm radius) infiltrated with the blood sample is punched out with a commercially available punch, glucose is eluted from the filter paper with a haemolyzing solution and subsequently glucose concentration determined by whatever method is available. Using the hexokinase method, this gives satisfactory precision and unimpaired accuracy. It compared well with the frequently used sampling with capillary tubes, correlating with an r value of 0.9932. The sample, obtained as described, is insensitive to light, temperature, humidity and time interval until measurement. Glucose concentration remains stable under various conditions for at least four weeks.

Blood Chemical Analysis↗
PubMed1979

Evaluation of preservative fluid for urine collected for culture.

Immediate culture or refrigeration of urine is recommended, but not always practical. Therefore, we evaluated the Becton-Dickinson Urine Culture Kit containing a boric acid-glycerol-sodium formate preservative in a study of 1,000 clinical urine specimens. Each specimen was cultured a total of four times by the surface streak technique with a 0.001-ml calibrated loop. After an initial reference culture (culture 1), a portion of urine was poured into a clean nonsterile paper cup, aspirated into a urine transport tube, and recultured immediately (culture 2). The original specimen cup was refrigerated for 18 to 24 h (culture 3), and the urine transport tube was held at room temperature for 18 to 24 h (culture 4) before repeat cultures. Eighty-eight of the initial reference cultures were positive (pure growth of greater than 10(5) bacteria per ml). Eighty-two (93.2%) of the 88 specimens positive on the reference culture were also positive after refrigeration or holding at room temperature in the transport tube for 24 h. There was one false-positive culture from refrigerated urine but none from the transport tube. Mixing of urine in a nonsterile container did not introduce detectable contamination. We conclude that the Becton-Dickinson Urine Culture Kit maintains a stable bacterial population in urine for up to 24 h as reliably as refrigeration. Urine for culture may be collected in a nonsterile container if it is immediately aspirated into the transport tube so that contaminants are not allowed to multiply.

Bacteria↗